ESDS - Economic and Social Data Service
http://www.esds.ac.uk/
The Economic and Social Data Service (ESDS) provides access for an extensive range of key economic and social data, both quantitative and qualitative.

Cathie Marsh Centre for Census and Survey Research (University of Manchester)
http://www.ccsr.ac.uk/
CCSR is a centre for applied quantitative research. Appart from methodological research it also provides primary data for researh topic such as 'Ethnic group, racial and cultural demography' or'Migration and health'.

UK Data Archive (UKDA)
http://www.data-archive.ac.uk/
The UK Data Archive (UKDA) collects, preserves, disseminates the largest collection of digital data in the social sciences and humanities in the UK. Founded in 1967, it now houses several thousand datasets of interest to researchers in all sectors and from many different disciplines.